30 sdi would be alot better cause most "tankmage" type only use one majic class. although do see its 4/6 so maybe 20 be ok with chiv / magery.
also dont know why your have undead slayer, unless its 45 hci youd be better off with other item in that slot.
for pricechecks people like to know:
if it uses a shield
if it uses a weapon / mageweapon